A light emitting device for a lighting instrument should provide white light through LEDs. A white semiconductor light-emitting apparatus may be generally realized by the following three methods.
First, three LEDs emitting the three primary colors of light, that is, red, green and blue, respectively, are combined to realize white light. Light emitting materials used herein generally include InGaN or AlInGaP phosphor. A second method is to use a UV LED as a light source to excite a three primary color phosphor, in turn emitting white light. In this case, an InGaN/R, G, B phosphor is used as a light emitting material. Third, a blue LED as a light source may excite a yellow phosphor, thus embodying white light. For this method, an InGaN/YAG:Ce phosphor is generally used.